In these examples, we've taken a look at a few strategies for implementing a new API using existing API backends. Another common scenario is migrating an existing API to a serverless architecture, without changing any of its functionality. In this scenario, we can still use the proxy pattern and API Gateway. With all of the work in place ready to go, how does one actually deploy a new proxy layer without affecting existing traffic or breaking these clients? The following are a few techniques and deployment strategies that you may consider when faced with this problem.
To replace an existing API with a serverless-based system, it makes sense to first implement the proxy pattern and define the complete API in API Gateway. Each endpoint would simply proxy requests and responses to and from their corresponding APIs on the system to be replaced.
It's even possible to start initial testing with what is called a proxy resource. With this model, one creates a resource...